Mobile cargo tanks can be used in different contexts to transport liquids, solids, sludges, slurries, mixed and pure liquids, and other materials. For example, storage tank vehicles such as chemical trucks can include a cargo tank trailer, configured to be hauled by a semi-trailer truck. Other arrangements can include cargo tanks configured for use with train carriages, with tanker trucks, or otherwise. In some configurations, cargo tanks can be designed to hold pressurized contents. In some configurations, contents can be non-pressurized.
In conventional mobile cargo tank designs, a manway and other equipment, such as inlet ports or couplings, can be disposed on, and extend through, a top or roof of the relevant tank. This can be useful, for example, in order to allow access into an interior storage area of the tank or to vent vapor or otherwise relieve excess pressure from the storage area. In some cases, a ladder can be provided for access to the tank roof, and the manway and other equipment can be surrounded by a balcony. Accordingly, during inspection and other operations (e.g., cleaning of the tank), an operator may be required to climb a ladder and clear a balcony (or other features) in order to access the manway and other tank inlets.
In different installations, conventional cargo tanks can also include a number of seals between the interior storage area of the tanks and the external environment. For example, seals can be provided on manway covers, at tank inlets (or outlets), at hose fittings (or other fittings), and so on. This can be useful, for example, to help to ensure appropriate material containment and handling of materials carried by the cargo tank. However, because operational procedures may require regular inspection of all relevant seals, the inclusion of multiple seals can require an operator to devote substantial time to seal inspection over the course of loading, transport, unloading, and other operations.